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991.
Twenty-two institutionalized handicapped children who were susceptible to varicella were vaccinated with live varicella vaccine of the Oka strain and their immune status was followed for 5 years under conditions without exposure to natural varicella. Simultaneously, 7 children infected with natural varicella were followed. Of the 22 vaccinees, 16 showed sero-positive conversion by the fluorescent antibody to membrane antigen (FAMA) test, the other 6 remaining seronegative during 5 years of observation period. All the 16 cases showing seroconversion had detectable antibody for 5 years after vaccination, and 14 of them gave a positive reaction in the varicella skin test. All the 7 cases after natural varicella gave positive reactions in both the FAMA and skin test. These results suggest that immunity conferred by the vaccination would persist long even in the absence of exposure to natural varicella, though further follow-up studies are needed.  相似文献   
992.
Thy-1 antigens are the only cell membrane antigens known to be able to induce primary antibody responses in vitro. We have shown that antigens from the thymocytes of mice and rats were highly immunogenic in cultures of murine spleen cells for the induction of Thy-1.1-specific plaque-forming cell responses, whereas antigens from other tissues, including brains and bone marrow, were poorly immunogenic, if at all. The thymocyte-specific Thy-1 immunogenicity was carried by disrupted cell membranes, and the specific activity for inducing responses was closely linked to Thy-1. We then tried to determine the mechanism of anti-Thy-1 antibody responses in vitro that were induced by the uniquely immunogenic thymocyte antigens. The thymocyte Thy-1 antigens behaved as T cell-independent class 2 (TI-2) antigens: they induced responses in athymic nude mice but not in CBA/N mice with a B cell defect. The apparent TI-2 responses to thymocyte Thy-1 did, however, require Thy-1+ cells in the responder, similar to anti-DNP-Ficoll responses. The full development of the anti-Thy-1 responses required the participation of splenic adherent cells (SAC). Nevertheless, the mechanism of the SAC dependency of anti-Thy-1 responses did not involve antigen presentation to lymphocytes by antigen-pulsed SAC, which contrasted with the finding that the presentation of antigen by live SAC to lymphocytes was indispensable for responses to DNP-Ficoll. The poor Thy-1 responsiveness of SAC-depleted spleen cells was fully restored by the addition of soluble factors (IL 1-like molecules) released from SAC into the culture, which did not replace the SAC-requirement of responses to DNP-Ficoll. It was concluded from these results that Thy-1 or Thy-1-linked structures on thymocyte membranes have an intrinsic activity to directly signal either TI-2 B cells or immature T cells, or both, for activation in the presence of soluble factors released from adherent accessory cells. This conclusion is discussed in relation to a hypothetical view that the thymocyte Thy-1 would physiologically mediate cell-to-cell interactions among special subsets of lymphocytes under thymic influence.  相似文献   
993.
Effects of the calcium ionophore, A23187, and antimycin A on the circadian conidiation rhythm of Neurospora crassa were examined. A23187 at a concentration of 1 mum in medium not containing divalent cations delayed the phase by 10 hours at CT 10 and advanced it by 5 hours at CT 14 (CT 12 corresponds to the time that discs are transferred from light to dark). This phase shifting was completely inhibited by addition of 0.1 millimolar CaCl(2) but not by MgCl(2) at any concentrations examined.Antimycin A inhibited respiration by 90% at a concentration of 0.2 micrograms per milliliter and lowered the ATP content by 85%. Antimycin A alone caused small phase advances but in combination with A23187 resulted in a large phase delay at CT 10. This phase shifting was not reversed by addition of CaCl(2) lower than 10 millimolar.  相似文献   
994.
Effects of respiratory inhibitors on the circadian clock, respiratory activity, and ATP content were examined in Neurospora crassa. All inhibitors, potassium cyanide, sodium azide, antimycin A, and carbonyl cyanide m-chlorophenyl hydrazone (CCCP), shifted the phase of the conidiation rhythm. All the phase response curves were similar and resembled that for cycloheximide, but were different from the phase response curve for light. Phase shifting by azide and CCCP was proportional to the lowering of respiratory activity and ATP content, but such a correlation was not observed for cyanide and antimycin A. In particular, cyanide at a concentration of 0.5 millimolar completely depleted ATP of the cultures but did not significantly shift their phase. Their results suggest that large shifts caused by these inhibitors are not due to a decrease in energy from respiratory activity.  相似文献   
995.
Cyclic AMP-dependent phosphorylation of a variant erythrocyte pyruvate kinase (PK; EC 2.7.1.40) was studied. This variant PK shows a faster electrophoretic mobility than the normal enzyme. The decreased enzyme activity observed in this variant is associated with a quantitative decrease of enzyme protein. Other parameters are within normal ranges. The partially purified variant PK is phosphorylated with a subsequent increase of k0.5s (phosphoenolpyruvate) similar to the normal control, suggesting that the structural abnormality of the variant enzyme has no influence on the phosphorylation-deactivation mechanism. On the other hand, the variant PK in the erythrocyte was less extensively phosphorylated than PK in normal erythrocytes. This may be the result of abnormal metabolism in the patient's red cells, including increased 2,3-diphosphoglycerate and decreased adenosine triphosphate levels.  相似文献   
996.
997.
The history of the deep north basin of Lake Biwa extends over 430,000 years. Although it has probably been oxic and oligotrophic since its formation, human impacts have been changing lake conditions. In this paper, we discuss long-term changes in the chemistry of bottom water by compiling literature and through our own data over the last half-century. Long-term records show an increase in temperature, decrease in dissolved oxygen (DO), and increase in nutrients in bottom water. The stoichiometry among oxygen and nutrients indicates that changes are basically consistent with aerobic decomposition of organic matter. These changes are most likely the result of global warming and local eutrophication. Of particular note, yearly minimum DO concentrations <50 µmol kg?1 have started to occur frequently at ~90 m depth since 1999. Manganese (Mn) concentrations in bottom water are at their minimum during the turnover period and at a maximum during the late stratification period each year. Yearly minimum Mn concentration has been within a narrow range over the last 30 years (0.25 ± 0.07 µmol kg?1, n = 12). However, abnormally high Mn concentrations (up to 9.3 µmol kg?1) were observed in 2007, caused by reductive release of a substantial amount of Mn from suboxic sediments and subsequent oxidation in bottom water. The concentration of arsenic (As) has gradually increased over the last 20 years in a similar manner, with a homologous element of phosphorus (P), resulting in an observed range of 17–29 nmol kg?1 in 2010. The accumulation rate was ~0.8 nmol kg?1 year?1 for As and ~6 nmol kg?1 year?1 for P.  相似文献   
998.
We developed a practical and reliable method for synthesizing an abasic deoxyribonucleoside, 1,2-dideoxy-d-ribofuranose (dRH) via elimination of nucleobase from thymidine. To synthesize oligonucleotides bearing dRH by the standard phosphoramidite solid-phase method, dRH was converted to the corresponding phosphoramidite derivative and linked to a solid support (controlled pore glass resin). Chemically modified small interfering RNAs (siRNAs) possessing dRH at their 3′-overhang regions were synthesized. Introducing dRH to the 3′-end of the antisense strand of siRNA reduced its knockdown effect.  相似文献   
999.
(-)-Epigallocatechin-3-O-gallate (EGCG), the most abundant polyphenol in green tea, mediates the oxidative modification of proteins, generating protein carbonyls. However, the underlying molecular mechanism remains unclear. Here we analyzed the EGCG-derived intermediates generated upon incubation with the human serum albumin (HSA) and established that EGCG selectively oxidized the lysine residues via its oxidative deamination activity. In addition, we characterized the EGCG-oxidized proteins and discovered that the EGCG could be an endogenous source of the electrically-transformed proteins that could be recognized by the natural antibodies. When HSA was incubated with EGCG in the phosphate-buffered saline (pH 7.4) at 37°C, the protein carbonylation was associated with the formation of EGCG-derived products, such as the protein-bound EGCG, oxidized EGCG, and aminated EGCG. The aminated EGCG was also detected in the sera from the mice treated with EGCG in vivo. EGCG selectively oxidized lysine residues at the EGCG-binding domains in HSA to generate an oxidatively deaminated product, aminoadipic semialdehyde. In addition, EGCG treatment results in the increased negative charge of the protein due to the oxidative deamination of the lysine residues. More strikingly, the formation of protein carbonyls by EGCG markedly increased its cross-reactivity with the natural IgM antibodies. These findings suggest that many of the beneficial effects of EGCG may be partly attributed to its oxidative deamination activity, generating the oxidized proteins as a target of natural antibodies.  相似文献   
1000.
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